The closed and capped Riverhead landfill on Youngs Avenue and the adjacent sand mine. Image: Google Earth

Chemical contaminants known to have a wide range of health risks have been detected at the Riverhead landfill site on Youngs Avenue at levels up to more than 10 times the state drinking water standard, prompting an investigation by environmental and health officials into potential contamination of nearby private wells.

Sampling at existing monitoring wells at the Riverhead landfill, which closed in 1993, showed maximum concentrations of 110 parts per trillion (ppt) for perfluoroctanoic acid (PFOA) and 49 ppt for perfluorooctanesulfonic acid (PFOS), the New York State Department of Environmental Conservation said. Under new drinking water standards adopted by the state last year, the maximum level for both contaminants is 10 ppt.

In light of these findings, offsite drinking water wells downgradient of the landfill — that is, northeast of the site — will be tested for PFAS, according to the DEC, which has so far identified 15 private wells at risk. These wells will be sampled by the Suffolk County Department of Health Services, according to the DEC.

Both chemicals — together called PFAS, which stands for per- and polyfluoroalkyl substances — are very persistent in the environment and in the human body – meaning they don’t break down and they can accumulate over time, according to the U.S. Environmental Protection Agency.

PFAS can cause reproductive and developmental, liver and kidney, and immunological effects in laboratory animals, according to the EPA. Both chemicals have caused tumors in animals. The most consistent findings are increased cholesterol levels among exposed populations, with more limited findings related to low infant birth weights, effects on the immune system, cancer (for PFOA), and thyroid hormone disruption (for PFOS).

Both of these manmade chemicals, manufactured and used since the 1940s, are no longer produced in the United States but still enter the domestic marketplace in a variety of products and remain very commonly used.

PFAS can be found in food grown in PFAS-contaminated soil or water, in food packaged in materials containing PFAS, and food processed with equipment that used PFAS. The chemicals can also be found in common household products, including stain- and water-repellent fabrics, nonstick products (e.g., Teflon), polishes, waxes, paints, cleaning products, and fire-fighting foams. Some industrial processes, such as chrome plating and electronics manufacturing also use PFAS.

The contamination at the Riverhead landfill was detected by sampling of the landfill’s groundwater monitoring wells during a statewide investigation of nearly 1,900 inactive landfills by the State Department of Environmental Conservation.

The DEC notified Riverhead Town officials, including the supervisor, town council members and the water district superintendent by email on Sept. 9.

“DEC is conducting a comprehensive investigation at the Riverhead landfill site,” the DEC said in an email to RiverheadLOCAL last week.

“DEC is working closely with the New York State Department of Health and Suffolk County Department of Health Services to perform a full evaluation of any potentially impacted drinking water wells to ensure the protection of public health and the environment,” the agency said.

If drinking water wells are affected, the DEC said “mitigation would be undertaken wherever necessary to prevent exposure to contaminants and ensure the protection of public health.”

There are no public water supply wells downgradient of the landfill site, Riverhead Water District Superintendent Frank Mancini said in a phone interview Thursday.

Landfill findings heighten concerns about adjacent sand mine expansion

Mancini and other town officials have expressed grave concerns about an application to vertically expand an existing 15-acre sand mine on a 20-acre site bordering the closed and capped landfill. The mine operator proposes to dig an 8.5-acre portion of the site to a depth of 100 feet — 89 feet into groundwater.

The town has sued the DEC and the mine operator, seeking an order requiring a full environmental review of the potential impacts of mining deep into the groundwater aquifer adjacent to a closed and capped landfill.

There is “strong potential” the mining will affect groundwater flow and draw landfill leachate toward the mine, providing “a major pathway for chemical transfer” that could impact the aquifer, according to the town’s petition. But the DEC, which took lead agency for purposes of environmental review — over Riverhead’s objection — chose not to analyze that when it issued issued a determination of non-significance under the State Environmental Quality Review Act, meaning the application would not be subject to a full-blown environmental review.

The detection of PFAS at such high concentrations in groundwater below the landfill heightens the town’s concerns about the expansion of the adjacent mine, Mancini said.

The lawsuit was filed in late January and served on the state and the mine operator in February. The defendants have not yet filed a response to the town’s petition, per a stipulation adjourning the action, most recently to Oct. 5.

PFAS detected in other drinking water wells

PFAS have been detected at levels above the state maximum contaminant level (MCL) in other locations in Riverhead.

PFOS has been detected in one of the water district’s own wells, located on Middle Road east of Northville Turnpike at a level above the state’s 10 ppt MCL. There are two wells at that site and the district is blending water pumped from each; the blended water meets state standards, Mancini said.

Riverhead was in the process of designing a $5.1 million granular activated carbon filtration system to remove manganese from the affected well when the PFOS was detected. The filtration system will remedy the PFOS contamination as well, according to officials. The town has obtained a deferral from the state allowing it more time to comply with the strict new drinking water standards.

The town has hired an environmental law firm to sue the manufacturers of PFAS for damages related to the contamination of the water district’s drinking water supply.

PFAS has also been detected at more than three times the MCL in a private residential well on the west end of Middle Road in Calverton. It is one of five homes in the area, which currently has no access to a public water main, that were identified through well-water sampling, as impacted by volatile organic compounds (VOCs) including Freon-12, PFAS and 1,4 Dioxane.

The DEC is currently providing bottled water and performing quarterly drinking water sampling at five homes and one business on Middle Road that are not served by public water, the agency said last month. The DEC in addition has also offered one of the five homes a whole-house water treatment system due to PFAS contamination. A second home already had a water treatment system installed. The wells at three other homes were contaminated with Freon-12 and 1,4 Dioxane, which cannot be effectively removed by point-of-entry water treatment systems, the DEC said.

Residential and agricultural uses in that area of Calverton have coexisted with nearby long-term industrial uses, such as Suffolk Cement on Middle Road and Coastal Pipeline Products on Twomey Avenue. The area has been zoned for industrial uses since the town first adopted a zoning ordinance. New uses recently proposed for the same area include a materials processing facility adjacent to Suffolk Cement and a propane distribution facility on Middle Road. The propane facility application has been withdrawn.

PFAS and other contaminants, including several types of solvents, the gasoline additive MTBE, and the chemical commonly known as DEET were detected in private residential wells in Manorville and Calverton south of the former Naval manufacturing plant in Calverton. That area is also not served by public water. The town has drawn plans for water district extensions to serve that area, but is seeking state and federal funding to cover the cost.

PFAS have been detected on the Navy’s former plant, which was operated by Grumman Aerospace (later Northrop Grumman) for decades. Grumman, as Navy contractor, manufactured and tested fighter jets for the Navy at the Calverton plant. PFAS are used in firefighting foam and firefighting foam was used at a firefighting training area on the Navy’s site in Calverton.

The Navy has disavowed responsibility for any offsite groundwater contamination and has said it will not be held to New York State’s recently enacted drinking water standards for PFOS, PFOA and 1,4 Dioxane. Navy representatives told residents and officials at community meetings last year the Navy is bound only by federal drinking water standards, which are essentially nonexistent for these so-called “emerging contaminants.”

According to documents in a federal lawsuit between Northrop Grumman and its liability insurance companies, the Navy and Northrop Grumman knew as far back as the mid-1980s that the company’s operations on the site had contaminated groundwater. A 2013 court decision in that case, revealed that Grumman knew that groundwater contamination resulting from its operations could migrate off-site and threatened drinking water as well as the Peconic River estuary.

Private well testing in that area was undertaken by the Suffolk County Department of Health Services in cooperation with the Suffolk County Water Authority.

Mancini said Thursday there are only 198 private wells left in Riverhead Town, which he said was far less than most other towns. Many of those locations are not close enough to existing public water mains to make connection costs feasible, since an extension is typically paid for by taxes on the properties to be served by the extension. That makes connecting the homes south of the former Navy facility cost-prohibitive unless there’s federal or state funding available.

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